Características fisiológicas, produtivas e nutricionais do capim faixa-branca submetido a estratégias de desfolhação intermitente

Abstract

The objective of this study was to evaluate the physiological, productive, and bromatological parameters, the structural characteristics and the dynamics of the tiller population of digit grass (Digitaria eriantha Steud cv Suvernola) submitted to combinations of two pre-defoliation heights (40 and 50 cm ) and two post-defoliation (10 and 20 cm), during periods of higher sunshine (September to March) and lower insolation (April to August). The design was in a randomized block design, with five replications. Defoliation management was done with mechanical cuts. During the evaluation period the experimental area was regularly irrigated. During the period of greatest sunshine, the total Falker chlorophyll index (ICF) was similar among defoliation targets. However, for the period of lower insolation, total ICF was higher in the 40/20 and 50/10 targets. The maximum quantum efficiency of FSII (Fv / Fm) in the period of greatest insolation was also similar among defoliation targets. It was observed that in the period of lower insolation, higher Fv / Fm was obtained when the 40/20 target was used and the lower value was in the 50/20 defoliation target. Greater accumulations of total forage and leaf blades were observed for the defoliated digit grass in the 40/20 defoliation target, with a higher crude protein content, in the period of greater insolation, and lower levels of neutral and acid detergent fibers, independently of the period evaluated. On the other hand, the canopy defoliation in the 40/10, 50/10 and 50/20 goals provided greater stunting. It was also observed that with the use of the 40/20 defoliation target the digit grass obtained larger amounts of generations of basal and aerial tillers, with a higher density of basal, aerial and total tiller. Stability indexes of the basal and aerial tiller population remained close to 1.0. The use of the 40/20 defoliation goal gave the digit grass better physiological, productive and bromatological characteristics when submitted to intermittent defoliation strategies.